@Kraco: She may need to slap it. At the very least she needs to concentrate to use her powers.

@Shinta: Heroes have many qualities which they assessed: intelligence, threat elimination proficiency and selflessness. The last bit needs to be hidden from examinees, which was the case here. It doesn't work if you have perceivable gains from your actions.

What shouldn't have happened was to have All Might talk about the secret part of the exam to a candidate.

You don't have to be self-sacrificing to be a hero, which is why there's no minimum score.

To answer your original question: "Isn't that worthy of being failed? Are they just gonna leave someone to die in the real world if it isn't convenient for them?".

No, it's not an automatic fail. You can still maintain peace without being entirely selfless.